Our study elucidates how forest type characteristics and human presence influence bonobo (Pan paniscus) densities and assesses whether the Salonga National Park harbors a substantial bonobo population. We searched 11 locations in the Salonga for the presence of bonobos and sampled 9 study sites using line transects to estimate relative bonobo nest density, the proportion of forest types, and the intensity of human activity. We classified forests into broad types by overstory and understory composition, canopy cover, and hydrology, and calculated encounter rates for bonobo, human, and large mammal signs. Bonobo signs occurred in 8 of 11 locations but varied widely in frequency. Mean density was 0.72 nest-builders/km2, but density was not uniform across sites (range=0–2.8 nest-builders/km2). Of 11 forest types encountered, the most common were mixed mature forest with an herbaceous (Marantaceae) understory (36.8%), with a woody understory (23.6%), and old secondary forest with a Marantaceae understory (10.5%). Nest sites occurred only in these forest types, called nest-forest types. Bonobo density was highest in locations comprising >80% nest-forest types. Nests occurred more frequently in the mixed mature/Marantaceae forest. Nest-site density correlates positively with the nest-forest patch length we encountered on transects, implying that forest patch size and consistency may influence bonobo density. Mean nest group size correlates positively with proportion of nest-forest types found at a site, suggesting that increased resource availability—nesting sites and food—allows larger group size. A significant inverse association existed between bonobo density and human presence.

Susman, R. L. (1995). The only way to determine the conservation status of the pygmy chimpanzee is to conduct a survey in the Zaire Basin: a reply to Dr. Kortlandt. Primate Conserv. 16: 37–39.Google Scholar

Thompson, J. (1997). The History, Taxonomy, and Ecology of the Bonobo (Pan paniscus, Schwarz, 1929) with a First Description of a Wild Populations Living in a Forest/Savanna Mosaic Habitat, Doctoral Dissertation, University of Oxford, Oxford.

Van Krunkelsven, E., Inogwabini, B. I., and Draulans, D. (2000). A survey of bonobos and other large mammals in the Salonga National Park, Democratic Republic of Congo. Oryx 34: 180–187.CrossRefGoogle Scholar

Copyright information

Authors and Affiliations

1.We dedicate this paper in humble gratitude to the Sandra and Fred Young family in recognition of their exceptional interest and generous support to ensure that bonobos survive in their homelandWisconsinUSA